Although specific lipids in bacteria can be quantitated, there is still a need to quantitate the total lipid content of a bacterial sample. The sulfo-phospho-vanillin reaction for quantitation of bacterial lipids has significant advantages over traditional methods for screening of engineered mutant strains. In this report we show that this methodology can be used directly on whole cell or homogenized biological material, without any extraction step. The cell components, and most of the reagents used for cell extraction, that were tested did not interfere with the reaction. The screening is based on the observation of physiologic variations using ratios of relative amounts: lipid/DNA and lipid/protein. Our results show that significant differences in those ratios can be detected when there is a modification of the phospholipid content of the cell. The sample manipulation required is minimal and could be automated. Used as a primary screening and/or characterization of engineered mutant strain, the test may lead to further investigation of the nature and distribution of lipids in the cell.

Author Keywords: Bacterial membrane; Cell division; DNA; Lipid quantitation; Sulfo-phospho-vanillin reaction